The instant invention relates to a device for switching a coil between a state where it is fed and a state where it is used as a receiver. Thus, the instant invention aims more particularly at the switching of a coil used in relation with a videotape recorder magnetic head liable to serve as a read/write head.
In the read state, one of the terminals of the coil is grounded and the voltage on the other terminal is detected. In the write state, the terminal which was grounded is connected to a current source and the other terminal is connected to a power supply voltage, means being provided for modulating the current source and letting a current flow in the coil as a function of the signal to be recorded.
When it is desired to switch from a state to another, it is essential to avoid that a voltage be impressed to the coil when its other terminal is directly grounded and conversely that this other terminal be connected to the ground when a voltage is being impressed onto the coil. Indeed, overcurrents might occur as well as overvoltages impairing the operation and the lifetime of the device.
In the prior art, in order to resolve this problem, one has generally made use of devices, difficult to integrate, and comprising a high number of switches, the operation of which is to be precisely synchronized by means of complex processes.
One object of the instant invention is to provide for such a switching device which is particularly simple, comprises few switches, and is easily integrable.